Battery-Free RFID Heart Rate Monitoring System

Abstract

The goal of this research was to design an RFID based wearable platform capable of continuous heart rate monitoring for infants. Two TechnikTex P180+B conductive fabric electrodes with interconnects were integrated onto a baby onesie and connected to an RFID heart rate detection circuit that used an on-off keying modulation scheme to transmit heart rate data. The quality of the output signals obtained from the TechnikTex P180+B electrodes had 98.90% correlation with that obtained from a standard MediTrace-230 foam electrode. An antenna connected to an RFID reader captured the RFID tag information and fed the data into a Raspberry Pi processor that was programmed to compute the heart rate. The real time heart rate was calculated by using a four-heartbeat moving average window with an acceptable error rate of 3 bpm. The calculated heart rate was then communicated to a mobile app via Bluetooth. The app displayed the heart rate as a discrete value and also as a real time graph. A local alarm system integrated with the Raspberry Pi was used as an emergency backup system to alert in case the baby’s heart rate was not in the range of 80 bpm to 180 bpm and/or in case there was a communication failure between the RFID tag, RFID reader, processor or the mobile device.